Inhibitory effect of tungsten carbide nanoparticles on voltage-gated potassium currents of hippocampal CA1 neurons

The effects of tungsten carbide nanoparticles (nano-WC) on the properties of voltage-dependent potassium currents and evoked action potentials were studied in the hippocampal CA1 pyramidal neurons of rats at the ages of postnatal days 10–14 using the whole-cell patch-clamp technique. The results indicated that: (1) the amplitudes of transient outward potassium current (IA) and delayed rectifier potassium current (IK) were significantly decreased by 10−7 g/ml nano-WC, while the current–voltage curves of IA and IK were significantly decreased by nano-WC from +10 to +90 mV. (2) Nano-WC produced a depolarizing shift in the steady-state activation curve of IA and IK with increased slope factors, and delayed the recovery of IA from inactivation, but no significant effects were found on the inactivation of IA. (3) Nano-WC prolonged the evoked action potential duration and lowered the firing rate. These results suggest that 10−7 g/ml nano-WC can decrease the amplitudes of IA and IK currents by reducing the opening number of voltage-gated potassium channels and delaying the recovery of IA from inactivation, which indicate that nano-WC has the potential neurotoxicity.

► This is the first study of neuro-safety of tungsten carbide nanoparticles (nano-WC). ► The effect of nano-WC on CA1 neurons was investigated using patch-clamp technique. ► Results showed that 10–7 g/ml nano-WC can decrease the amplitudes of IA and IK. ► Results suggest that nano-WC has the potential neurotoxicity.